Transparent, conductive films have a wide variety of uses and have in recent years become increasingly important in the electronics industry. Such films are required for numerous devices such as television camera vidicons and liquid crystal displays.
Semiconductors oxides that have been utilized to form transparent conductive films include, for example, stannous oxide, indium oxide, cadmium oxide and the like which may be doped with antimony, indium, fluorine, and the like. One problem inherent in films prepared from these materials is that they have absorption edges in the near UV or in the blue end of the visible spectrum. Most electronic devices have poor blue response, and the absorption characteristics of such films aggravate the situation considerably. Where transmission at the blue end of the spectrum is critical, stannous oxide films are usually utilized because their absorption edge occurs further into the UV than other materials. Stannous oxide films, however, are disadvantageous in that their resistivity is higher than other semiconducting oxide films.
In many applications of transparent conductive films, transparency must be sacrificed to maximize conductivity and vice versa. An example of an application of transparent conductive films where conductivity is maximized at the expense of transparency is liquid crystal displays. In certain other applications, transparency and/or conductivity must be sacrificed for another critical property or properties such as, the necessity that deposition techniques be compatible with the intended substrate, etchability and the like.